Hydraulic coupling



w. 'r. STEPHENS 2,382,114

HYDRAULIC COUPLING Filed Dec. 14, 1942 2 sheets-sheath 14 52 ,MAWJJMM 6O Patented Aug. 14, 1945 2382,11! h HYDRAULIC COUPLING William T. Stephens, Cleveland, onicijassignbr toHydraulic Control Engineering Company,

Cleveland, Ohio, acorporati on of Ohio Application December 14, 1942,.SerialNo. 1 69,015

' 9 Claims. (01. 192-51) This invention relates to an improved form. of

hydraulic coupling-which may beused to connect a pair of driven and drive shafts in a-flexible'as well as a positive manner.

'It'has-previously been known to couple a driven advantages thereover because it employs a pressure sensitive check valve means which is dependent. only upon the rateof deliver-y oipressure fluid by the pump meansin response to relative rotation of the pump elements associated respectively-with the driven and drive. shafts.

That is to say, the valve meansis directly responsive to the pressure fluid delivered by the pump means,.and not to a centrifugal force resulting from rotation of the driven shaft.

A specific feature of the present invention is the disposition of the valve means coaxiallywith the axis of rotation of the coupling in the preferred embodiment, and perpendicular thereto in the modifiedembodiment, so that in each instance centrifugal-force has little Or no eifect upon t eoperation of the coupling.

Another object attained by the inventionis the provision of a hydraulic coupling havinga' form of valve means which will permit a small flow of pressure fluid when in closed. or partially unseated position in order that the-engine or other means connected to the driven shaft may turn over slowly without causing rotationof the drive shaft.

Another feature ofnth'e inventionexemplified inrits. preferred embodiment icomprises the -arrangement of a single valve means to control the flow of pressure fluidsfrom a plurality of pumps driven by the coupled shafts. v Other novel features of improvement contributing to the ease of manufacture of suchcoui plings and smoothness and efiiciency in operation will be perceived and'readily understood from reading the following detailed description of two illustrative embodiments of the invention in connection {with the which accompanying drawings, in

V Fig. 1 shows a vertical longitudinal section of the preferred form of hydraulic coupling;

Fig. 2 is a transverse section itakenalong the line II-II of Fig.1; I v a Fig. 3 isa longitudinal vertical section showing a modified form of the hydraulic coupling; and

Fig. 4 is atransverse section of the hydraulic coupling of Fig. 3 taken on the line IV'-IV.

I In'Figs. 1 and 2 which-illustrate a preferred embodiment of thehydraulic :couplingof this invention-,a sealed coupling housing [0 of cylindrical outline is divided: transversely into ahousing section l2,. and aninter-engaging housing section 14 rigidly united by a plurality of circumierentially spaced cap screws plBpOI any other conventional means which may be suitable. It

'Will be seen thathousing section l2 has an outwardly extending integral hub portion I8 formed to provide a couplingdriveshaft 20 of somewhat smaller diameter. v p

' An internal rotor designated generally as}: is closely fitted for rotation within the" coupling housing "Land provided vwith-an integraLdriven shaft-14 extending through an opening 26 in housing section I4 and supported by a conventional bearing 28mounted within-the outer end of, the housing section l4. Outwardly of the bearing 28 a'shaft seal -:30- of common formengages therotatable driven shaft 24 to prevent the escape of thefluid used for the coupling. At its other end the-rotor 22 has a short stub shaft -32 extending within the hollow'hub portion." vof the housing section l2 and journaledwithin suitable supporting bearings indicated as.34..

' As appears best. in Fig. 2, the housing section llhas a-ring gear 36 rigidly secured thereto by means such as a key 38and a similar diametrically-opposed key 40.- A shouldered joint 42 between the opposed faces of the housing sections l2 and i4 provides-means for locking, the keys 38 and 40in positiomas will'be apparentfrom -;a. consideration of Eigl v 1. Within the ring gear 35 is'closely-fitted areduc ed end 44 of the rotor 22 which endnis formed to provide diametrically opposed relieved. portions 46 and 48, respectively,

having central, semicircular recesses 50 and 5 2 encompassing theimier halves of pinion gears 54 and 56. Pinionl'gears 154 and 56 have respective bearing pin supports 58 and so in diametrically opposed portions of the ,reduced part 44 of .rotor. 22.

The right end of the rotor 22 as viewed in Fig.

1 isjcored outt'o form a symmetrical reservoir recess 62 for supplying oil to thetwo gear comprised by the pinion gearsv 54 and andthe engaging ring gear 35. Two gear pu'mpsare" preferred, but additional ones may be used, particularly,; for. large couplings. The reservoir recess 5; communicates with the pinion gear 54 by means 3 of an L.-shape suction passage 64 formed in the rotor 22; and an identical L-shape passage 66 f of the invention.

supplies the pinion gear 56 on the opposite side of the coupling. Within the ring gear 36 the left end of the rotor 22 is still further cored to provide a common high pressure main 68 of reverse 1 curve or approximately Z-shape intersecting an annularchamber in of. a check valvehor l2 which is coaxfalwith. the axis of. coupling rothe'rotor 22 and serve simultaneously to direct The form and disposition of the: check valve. bore 12 constitutes one of the important aspects It will be observed that this bore 12 has a reduced opening 14--communicat'- ing directlyand freely with the reservoir recess 1 62, and also providing an abutment stop for skirt ,7 fixed relation between their speeds of rotation for high pressure fluid from the delivery side oi the j pump gears 54 and 56 to the central valve loore'l2.

a given engine speed.

Ast'hespeed of driven shaft 24 is additionally increased, the speed of drive shaft approaches .synchronismtherewith so that there will eventually be acond ition when the two shafts are turning at the same speed. This one-to-one '1 :l')- ratio is attained when the pressure sensiend E6 of a hollow valveplungerj [8. At its'other end the. valve plunger 18' base. sfllidi for engagement with. a. stop:- plug 62 threaded. intothe short stub shaft of: the rotor 22, andv ahighpressurefiuid sealing gasketfld omits outer and within the coupling housingitfltl A coiled compressiorr' 'springtfi with-inthe plunger I T8- acts yieldingly to: maintain. the plunger head 86 in abutment with the adjacent endiof? stopplug 82 so theta lateral restricting port-or orifice 88 disposed in the sideof the plunger.' 'k8i a'dI- iacen-t itshead 86 is irr commimioationwith the annular chamber 16* receiving-high pressure flui'd from both geanpumps. the positiom 'illus trated- Fi 1, and-withrelativerotation inithe direction indicated by the arrow of'Flg. 2, pressure fluid from the" annular passage chamber 10 will seasona ee inwardiy'through the plunger will be assumed-that the drivemshaf't 24 is com nected tofa gas engine or any other'yariable speed rota-ting motive force, that the con tivevalve plunger 18 has been urged far enough to the right of Fig. 1 to close its side port or orifice 88, and: establish a hydraulic lock with an attendant direct transmission oi? motive. force from the. driven shaft to. the drive shaft; this to be observed in this connection: that the: fit of'the valve. plunger 1:8 in its bore 152 and that of" the stop plug 81 will; permit pressureflu'rd' to act upon-the outside ofithe plunger heard at all times.

space normally constituting reservoir 62. From this latter space itwould flow through passage 14', valve bore 12, and orifice port 88a to passage 68 When this reversal occurred, the valve plunger' [8 would beurged to the left against the stop plug 82, asthere would no longer be a pling drive shaft 20: is connected to the mechanismto be driven, such" asa vehicle wheel, for

example. For this application oftlre invention,

the orifice 88? of the valve plunger F8 and its seatingspring' 6 6 will be so proportioned; that at idling speed of the engine, or other driving pumps willpass through the orifice 88 22 is, enabled to: revolve freely withiri -the' housing ringgear 36 to provide a non-rotating or one hundred; per cent (100% )1 slipping drive. As the speed. of the engine is in-creased, thevolume of oil pumped will be correspondingly increased, 1 and av high, pressure area is. built up ,inthe an- I nular chamber .16 and is, in turn, carried back to the high pressure pockets of the pumpsaclj jacent the, respective .ends of the commonhigh pressure main 68",, thus slowing; up or retarding 1 the rotation of thesepumps. latter condi- 1 tion exists, however, only'jbeca-use the" housing sectionsflj and Iffresi'st rotatiorrdue to the-load coupled to drive shaft 20.; When theinertia'of this load is no longer sufiiment tocoun-teract the source of high pressure fluid opposing: the valve spring 66'. @fficourse; after the drive shaft 20 slowed down. to its proper relative. speed, normal or driving conditions'wouldagain prevail.

Except for the details which will; bev emphasized, the-twovalve formrof hydraulic coupling shown inFigs. 3 and 4 isiquite 'simi'larito-theipreferrecl embodiment which hasbeen described: com- 5 means; the; volume ofoil pumped by the two gear I pl'et'ely.

The internal rotor 2211' of: the modified coupling .is-provided with the integral outwardly driven 'shaft- 240- asbefore, and the-other end of the divided coupling housing E66 includes the drive shaft 26. The oppositely disposed pinion gears 54 and 56- arejourna'ledin the internalzrotor 220 andcoopera-te with the ring gear 36 in the same manner as already described to" afford: afiuid coupling between. the driven shaft Mmand the drive shaft 20. The rotor 220 also includes centrally recessed, relieved portions 4.60 and 4803 providing a high pressure and: low pressure side for each 'ofithe gear pumps;

Instead of a common high pressure-passageway,

the rotor220, which is cored to. provide a coaxial reservoir 62m and 'a-reduced connecting bore 622, has a pairof parallel, tangential passage ports 626 and 628 leading from the reduced bore 622 of the reservoir to another pair of outwardly disposed and'parallel fluid passages no and 660. The normal driving relation of this coupling is with the rotor 22!) turning as indicated by the arrow in Fig. 4. Accordingly, the parallel fluid passages 640 and 660 which extend between the relieved portions l60 and 480 have high pressure end portions 642 and 662, respec tively, extending in the reverse directions shown by Fig. 4. Since the valves in each of the passages 640 and 666 are identical in construction, only one will be described in detail. In passage 660 a side ported stop collar 96 is arranged forcommunication with the small reservoir port 626 and maintained in that relation by a two-piece set screw assembly 92 countersunk and accessible from the outer periphery of therotor 220. The skirt 160 of the hollow valve plunger 186 receives a coiled compression spring 860. Each plunger 180, in the I position illustrated, has its head 800 abutting a seat formed by the reduced end portion 662 of the passage 666, leaving the lateral restricting port or orifice 880 of the plunger 180 open either to annular. recess 94 or 9601? passages 640 and 666 respectively.

It is to be particularly observed that the length of the spring 866 when free from compression is appreciably less than the distance between the stop collar 96 and the proximate end of the valve head 800. Consequently, the valve plungers 180, 180 can be unseated far enough by fluid pressure without compressing the relatively strong spring 866 to permit a flow of pressure fluid from passages 642 and 662, respectively, into the corresponding annular recesses 94 and 96 and the individual restricting ports or orifices 880. To avoid chatter of the valves and even their partial opening before some pressure is built up by the pumps having gears 54 and 56, each valve plunger 180 is provided with a relatively weak spring 862 of such a diameter as to surround the exposed part of the heavy spring 660. One end of the spring 862 is seated on a reduced shouldered portion 864 formed on the outside of the valve skirt 160, and the other end abuts the adjacent end of the stop collar 90, so as to exert a valve-seating force at all times.

With only a single heavy spring actionto seat the valves, there is likelihood of a jerky and unsatisfactory action of the coupling. The reason is that a considerable pressure would have to be built up by the pumps before there could be any by-passing of the fluid into annular recesses 94 and 96, and, since no desired starting or load pick up slippage can occur in the coupling until there is such by-passing, the coupling would start in a positive drive relation. Then additional load im osed on the drive shaft 20 would create more hydraulic pressure which in turn would unseat the valve plungers 180 and produce slippage. The immediate drop in pressure upon unseating of the valve plungers [80 would permit the heavy springs to return the plungers 180 to their seats, resulting in jerky action by repetition of the cycle.

For example, a lightly loaded automotive truck of large load capacity and having correspondingly heavy valve springs would tend to move immediately as soon as the engine was started, but increase in load, as when the truck reached a hill, would increase the holding pressure required and result in the erratic action which has been described.

In addition to the functional characteristics which will be described in connection with its operation, the rotor 220 of the modified form of hydraulic coupling offers some advantages by way of simple machining of its internal passages.

The reservoir portions 620 and 622 which are coaxial with the driven shaft 246 have a still smaller filling passage 624 closed by a screw plug 820. It is a, simple matter to drill the tangential passage ports 626 and 628 becauseof their direct alignment with the opening for the set screw means 92. For the same reasons, the drilling of the straight and parallelfluid passages 646 and 660, which extend completely. through'the rotor- 220 on opposite sides of its axis of rotation,'is a simple matter, as is also the assembly of the ported stop collars 90 and valve plungers I80 therein.

With the direction of relative rotation shown in Fig. 4, the gear pump having pinion gear 54 will deliver high pressure fluid to the smaller end 642 of fluid passage 640 and the other gear pump having pinion gear 56, will supply high pressure fluid to the adjacent end portion 662 of the fluid passage 660. The low pressure sides of these two gear pumps will receive a supply of oil or other hydraulic fluid from the rotor reservoir 620 through the respective passages 626 and 628 in open communication with the collar 90 of each valve, at such times as fluid is not available from the high pressure side of the other pump.

When the coupling drive shaft 20 exceeds the speed of the driven shaft 240, as would occur if the driving engine were decelerated quickly after the coupling had been turning at high speed, the two gear pumps would supply pressure fluid in a reverse direction to the parallel fluid passages 640 and 660 whence it would return to the reservoir 620 by way of the ported stop collars 96. Since the reversed flow of oil allows valve heads 800 to return to their seats, thus preventing any flow of oil through passages 642 and 662 to the low pressure sides of the pumps, the opposed flow of high pressure oil from the two pumps builds up a pressure in reservoirs 620 and 622, passages 640 and 660 and relieved portions'460 and 480 which tends to lock gears and 56 in positive relation with ring gear 36, thus resulting in both drive and driven portion of the coupling revolving in synchronous relation with one another. This action produces a braking effect due to the resistance set up by the motive force or engine resisting rotation. When the speed of the entire unit has slowed down to the point where the load no longer reacts to drive the engine, normal operation is again restored. Operation of this nature is used to great advantage in the case of an automotive type vehicle going down hill and using the engine as a partial brake in holding back the load. This same action also takes place when a vehicle of the automotive type is stalled on a hill for then the action of the load would'te'nd to turn the pumps in the reverse direction and produce the same results.

While the 'reverse locking action as explained has been limited to the two valve coupling of Figs. 3 and 4, and the retarding action to the one valve coupling of Figs. 1 and 2, either action may be obtained in each of these two forms of couplings, by suitable coring and machining of the passages for the hydraulic fluid.

It is to be particularly noted that the valve plungers in both embodiments of the invention are arranged for movement in a direction which is perpendicular to the centrifugal force of coupling rotation.

Since other applications of the principles of the invention set forth herein will be apparent to those skilled in this art, it is not intended that the invention should be limited to any specific 1 details of construction or arrangement of parts claim: asnew and desiretozfsecure by Patentofthe United States is:

except be required: the scope -of' the ppendedclaims;

Having thus described Jmy: invention, what I 1. A'- hydraulic coupling of the character within said; housingand adapted to 'rotate with anothershaft, a ring gear secured within the said Letters 1 scribed, 'comprising'ra sealed housing adapted to rotate' -with a shaft, a closely fitted rotordisposed housing, pinion gears rotatably supported by said rotor at circumferentially:spaced. positions and arranged to mesh with: said ring gear soas to produce a gear pump action asthe rotor turns with respect'tothe housing, said rotor'being 1 formed'to provide fluid suction and delivery-pas- Y sages respectively leading to and from each'pump 3 pinion gear, and pressure sensitive valve means carried by the rotor and arranged between the delivery passages and the'suction passages, said valve'being constructed to unaidedly reduce-the flow therethrough. asthe vrelative pressure difference between said: passages increases, said valve 1 means being directly formed toop'ermit restricted flow of the pressure fluid at idling or slow 'relatiVe 'and rotor speeds; I 2. A hydraulic coupling of, thecharacter described, comprising a sealed housing. adapted; to

rotate with a driven shaft,; a closely fitted: rotor disposed within said housing and adapted to rotate a driving shaft, a ring gear within the said housing, pinion gears rotatably' supported} by said rotor at equally spaced positions and arranged-.110

of the valve means being exposed, to the fluid 1 pressure directly from the pumps and the said means being constructed to control the flow of pressure fluid-from thedelivery side of the pinion gears to the fluidreservoir of therotor, said valve means being formed to permit open but-restricted flow of the pressure fluid'to theireservoir at idling or slow driving speed.

3. A hydraulic coupling of thecharacter described, comprising a, sealed housing adapted to rotate with a driven shaft, a closely: fitted rotor 3 Y disposed within said housing and adapted to rotate with a driving shaft, a ring gear Withirr the said housing, a plurality-oi? pinion gearsrotat 1 ablysupported'by saidrotor at equally spaced positions and arrangedto mesh with"'said'i'ring gear so as to 'produce-aFgear pump; action?asv the rotor turns with respect to the housing, said rotor being formed; to provide a fluid reservoir having respective suction and common; delivery passages leading to each pump pinion gear, and T a pressure sensitive. valve means mounted co-' axially in the rotor and arranged to control the flow of pressure fluid from the: deliveryside of the pump pinion gears tothe fluid reservoir of' the rotor; said valve means including .a hollow plunger having an orifice therethrough to permit restrictedflow of the pressure fluid to the reservoir at idlingIorsl'ow: driving speed, said orifice being so restricted that it will not'accommodate the discharge of the pumpsv above idling speed whereby the valveisfully closed'solely by pressure.-- C

- 4.-A hydraulic coupling-of the character-described, comprising a sealed housing adapted to rotate with a driven shaft, a closely fitted rotor disposed within said. housing and adapted: to rotatewith a driving shaft, aring gear-secured within the said housin a pluralit of pinion gears rotatable supported by said rotor at equal- 1y spaced positions and arranged to mesh with said ,ring gear so-as to produce a gear prim-paction as the rotor turns withrespectto the housing, saidrotor being formed to provide a fluid reservoir having respective suction and common delivery passagesleadingto, each pump pinion gear, anda pressure sensitive check'valvemeans carried coaxiall-yby the-rotor transverselyof the common. delivery passage, which delivery passage is formed to provide an annular chamber around a portion of the-check valve and arranged to control the flow of pressure fluid from the delivery side of the pumppinion gears to the fluid reservoir of the rotor, said check valve'means including a hollowv plunger having an orifice laterally therethrough adjacent said. annular chamher to permit restricted flowof the pressure flu-id to the reservoir at idling or slow driving speed andvto block flow of the pressure fluid to thereservoir when the hollowplunger moves out of the so as to produce a gear pump action as the rotor turns with respect tothe housing, said-rotor being formed to provide a fluid reservoir having ducts leading to each pump pinion. gear, said ductseach including one of two parallel passages extending through the rotor in a direction. perpendioular to the axis of-saidrotor and on op-' posite sides thereofv so thateachof. said parallel passages will receive. high pressure fluid-from one of the gear vpumps andsupply low pressure fluid tothe other of said gear pumps, and .a pressure sensitive checksvalve means, carried by the rotor and arranged in each-of the parallel passages to control-the flow of pressure fluid from the delivery-side of the respective pinion gears, said check; valve means ,beingformed to reciprocate in theparallel passages-and permit restricted flow of the pressure fluid at idling or slow drivingspeei 1 I. I

61A hydraulic coupling otythepharacter described, comprising-a sealed housing adapted to rotate with a shaft, a closely fitted rotor disposed within said housing and adapted to-rotate with another shaft, a ring gear within the said housing, an. oppositely disposed-pair of pinion gears rotatably supported by saidrotor and arranged to mesh Withsaid ring gear so-asto produce a gear'pump action as the rotor turns respect to the housing, said rotor being-formed to provide pressure and suction chambers for each pump pinion gear, two parallel passagesextending through the rotor in a direction perpendicular to'the axis of said rotor and on opposite sides thereof so that each of'saidparall'ela passages will receive high pressurerfl'uid one of the gear pumps pressure i chambers and supply low pres sure fluid to the other of said gear pumps suction chambers, and a pressure sensitive valve means arranged in each of th parallel passages to control the discharge of pressure fluid from the delivery side of the respective pinion gears, said 5 check valve means each including a plunger reciprocable in one of the parallel passages and having a lateral orifice connected with a bore therethrough, and said parallel passages each being provided withan annular chamber extendl0 ing around the orifice of its valve plunger for delivering restricted flow of the pressure fluid when the valve plunger is unseated at idling speed, said lateral port being positioned to move out of the chamber and to block flow of the pressure fluid when the valve plunger moves sufllciently in response to an increase in speed.

7. A hydraulic coupling of the character described, comprising a sealed housing adapted to rotate with a shaft, a closely fitted rotor disposed within said housing and adapted to rotate with another shaft, a ring gear within the said housing, an oppositely disposed pair of pinion gears rotatably supported by said rotor and meshing with said ring gear so as to produce a gear pump action as the rotor turns with respect to the housing, said rotor being formed to provide receive-high pressure fluid from one of the 5 gear pumps and supply low pressure fluid to the other of said gear umps, and a pressure sensitive check valve means and arranged in each of the parallel passages to control the flow of pressure fluid from the delivery side of the respective pinion gears, said check valve means each including a hollow plunger reciprocable in and closing one of the parallel passages and having a lateral orifice therethrough, a light character described, comprising a sealed housing adapted for rotation with a shaft, a closely fitted rotor disposed within said housing and adapted to rotate with another shaft, internal ring gear teeth fixed in said housing, a pair of pinion gears rotatably supported by said rotor at diametrically spaced positions and meshing with said ring gear teeth so as to form two gear pumps effective as the rotor turns with respect to the housing, said rotor being formed to provide merged suction and merged delivery passages for said pumps and an axially disposed common passage connecting the merged passages, a pressure sensitive valve means slidably arranged in the common passage, which common passage is formed to provide an annular chamber around a portion of the valve and arranged to control the flow of pressure fluid from the delivery side of the two pumps, said valve including a hollow plunger having an orifice laterally therethrough exposed in said annular chamber to permit restricted flow of the pressure fluid at idling or slow driving speed and to block flow of the pressure fluid to the reservoir when the plunger orifice is moved out of the annular chamber in response to a predetermined increase in driving speed.

9. An automatic hydraulic coupling of the character described, comprising a sealed housing adapted for rotation with a shaft, a closely fitted rotor disposed within said housing and adapted to rotate with another shaft, internal rin ear teeth fixed in said housing, a pair of pinion gears rotatably supported by said rotor at diametrically spaced positions and meshing with said ring gear teeth so as to form two gear pumps efiective as the rotor turns with respect to the housing, said rotor being formed to provide merged suction and merged delivery passages for said pumps and an axially disposed common passage connecting the merged passages, a pressure sensitive valve means slidably arranged in the common passage, which common passage is formed to provide an annular chamber around a portion of the valve and arranged to control spring for constantly urging the hollow plunger 48 the flow ofpressure fluid from the delivery side into seated position and a strong spring for increasing resistance to movement after the hollow plunger has been unseated, and said parallel passages each being provided with a short annular of the two pumps, said valve including a hollow plunger having an orifice laterally therethrough exposed in said annular chamber to permit restricted flow of the pressure fluid at idling or chamber extending around the orifice of its valve 810W d ivin Speed nd to b oc w 0 t e p esplunger for delivering restricted flow of the pressure fluid when the valve plunger is unseated at idling speed, and to block flow of the pressure fluid when the valve plunger moves out of the annular chamber in response to pressure resulting from an increase in speed of the housing and rotor.

8. An automatic hydraulic coupling of the' a reservoir positioned on the suction side 01. said valve.

WILLIAM T. STEPHENS. 

